1. Field of the Invention
The invention relates generally to modular building systems, and more particularly to a modular building system for constructing multi-story buildings using prefabricated, precast concrete modular units that are disassembleable and repurposable.
2. Description of the Related Art
Modular units are commonly used for constructing residential and industrial structures because they can be partially assembled/constructed remote from the building site and transported via train, truck, or ship to the building site for assembly into a complete structure, such as an office building, for example. However, once the modular units are assembled into complete structures, the modular units cannot later be disassembled and reused in another structure or disassembled into repurposable or recyclable components. Further, in existing buildings constructed from modular units, the shear walls are not modular and instead must be constructed on site. Such non-modular shear walls are constructed by placing rods, beams, or a wire grid and pouring concrete on site, and thus cannot be disassembled and reused. Conventional modular units are typically in the form of a “box” that includes a floor and ceiling and external walls. Forming a structure from such units necessarily results in redundant floor, ceiling, and wall elements between units, which is inefficient.
Consequently, many otherwise sound modular units are wasted because they cannot be disassembled without being damaged or destroyed. Moreover, conventional modular units require some type of additional frame to support the modular units once they are stacked on top of, and next to, one another. Additionally, during assembly of the completed modular units into the final structure, wet trades must be employed at the construction site to couple the individual modular units together. Such connected modular units cannot be disassembled for reuse.
Currently, when modular units are assembled together at a construction site, a crane must lift and move the modular unit to an assembly position and hold the modular unit in position so that the modular unit can be connected to another modular unit. Scaffolds are typically constructed or moved around the modular unit to enable workmen to access the connection points of the modular units. For example, the connection point for a column is at the top of the column when the column is standing vertically. The process of moving/assembling various scaffolds around the construction site is time consuming, costly, and dangerous.